Master batch containing heat radiation shielding component, and heat radiation shielding transparent resin form and heat radiation shielding transparent laminate for which the master batch has been used

ABSTRACT

In a master batch containing a heat radiation shielding component, which is used to produce heat radiation shielding transparent resin forms, the master batch has as chief components a thermoplastic resin and a hexaboride represented by XB 6 , wherein X is at least one selected from La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr and Ca. The hexaboride, which is a heat radiation shielding component, is contained in an amount of from 0.01 part by weight or more to less than 20 parts by weight based on 100 parts by weight of said thermoplastic resin. The use of this master batch enables simple production of heat radiation shielding transparent resin forms having a high visible-light transmission power and a high heat radiation shielding performance, without relying on any high-cost physical film formation methods.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a master batch used in producing heatradiation shielding forms (extruded or molded forms) which are widelyutilized for roofing and wall materials of buildings, window materialsused at openings of automobiles, electric trains, aircrafts and soforth, arcades, ceiling domes, carports and so forth. More particularly,it relates to a master batch containing a heat radiation shieldingcomponent, used in producing transparent resin forms having goodvisible-light transmission properties and a superior heat radiationshielding performance, and also relates to a heat radiation shieldingtransparent resin form, and a heat radiation shielding transparentlaminate, for which this master batch has been used.

[0003] 2. Description of the Related Art

[0004] Solar radiations which enter various buildings and vehiclesthrough their “openings” such as windows and doors include visible-lightrays and besides ultraviolet radiations and infrared radiations. Amongthe infrared radiations included in such solar radiations, near-infraredradiations of 800 to 2,500 nm in wavelength are called heat radiations,and enter through the opening to cause a temperature rise in the room.In order to avoid such a temperature rise, in recent years, in the fieldof window materials for various buildings and vehicles, there is a rapidincrease in demand for heat radiation shielding forms which can shieldheat radiations while taking in visible-light rays sufficiently and canprevent the temperature rise in the room while keeping brightness.Patents concerning such heat radiation shielding forms are proposed in alarge number.

[0005] For example, a heat radiation shielding sheet is proposed inwhich a heat radiation reflecting film comprising a transparent resinfilm on which a metal or a metal oxide has been vacuum-deposited isbonded to a transparent form such as a glass sheet, an acrylic sheet ora polycarbonate sheet (see Japanese Patent Applications Laid-open No.61-277437, No. 10-146919, No. 2001-179887, etc.). However, this heatradiation reflecting film itself is very expensive and also requires acomplicate process having a bonding step and so forth, resulting in ahigh cost. In addition, the heat radiation shielding sheet has adisadvantage that the adhesion between the transparent form and thereflecting film is not so good as to cause peeling of the film as aresult of changes with time.

[0006] Heat radiation shielding sheets in which metals or metal oxidesare directly vacuum-deposited on the surfaces of transparent forms arealso proposed in a large number. These, however, have a problem that, inproducing such heat radiation shielding sheets, an apparatus isnecessary which requires environment control in a high vacuum and in ahigh precision, resulting in a bad mass productivity and poorgeneral-purpose properties.

[0007] Besides, also proposed are, e.g., a heat radiation shieldingsheet, and a film used therefor, in which an organic infrared absorbertypified by a phthalocyanine compound or an anthraquinone compound iskneaded into a thermoplastic transparent resin such as polyethyleneterephthalate resin, polycarbonate resin, acrylic resin, polyethyleneresin or polystyrene resin (see Japanese Patent Applications Laid-openNo. 6-256541, No. 6-264050, etc.). However, in order to shield the heatradiations sufficiently, the infrared absorber must be mixed in a largequantity. Its mixing in a large quantity leaves a problem that theability to transmit visible light rays may lower. Also, since an organiccompound is used, their use in window materials or the like forbuildings and vehicles which are always directly exposed to sunlightinvolves a difficulty in weatherability, and can not necessarily said tobe appropriate.

[0008] Further proposed is, e.g., a heat radiation shielding sheet inwhich inorganic particles of titanium oxide having heat radiationreflectivity or mica or the like coated with titanium oxide are kneadedinto a transparent resin such as acrylic resin or polycarbonate resin(see Japanese Patent Applications Laid-open No. 2-173060, No. 5-78544,etc). This sheet, however, requires addition of heat radiationreflecting particles in a large quantity in order to improve heatradiation shielding power, so that the visible-light transmissionproperties may lower with an increase in the quantity of the heatradiation reflecting particles mixed. On the other hand, the addition ofheat radiation reflecting particles in a small quantity may bring animprovement in the visible-light transmission power but may result in alow heat radiation shielding power. Thus, there has been a problem thatit is difficult to satisfy the heat radiation shielding power and thevisible-light transmission power simultaneously. In addition, the mixingof heat radiation reflecting particles in a large quantity involves aproblem in view of strength that transparent resin forms may have lowphysical properties, in particular, a low impact resistance and a lowtoughness.

[0009] Under such technical backgrounds, the present inventors havealready proposed a heat radiation shielding coating liquid in which finehexaboride particles are incorporated in a binder of various types, anda heat radiation shielding film obtained by coating a form of varioustypes with this coating liquid, followed by drying (see, e.g., JapanesePatent Applications Laid-open No. 11-181336, No. 2000-96034 and No.2000-169765).

[0010] In these proposals, however, nothing has been brought forwardwith regard to master batches used in producing heat radiation shieldingforms.

SUMMARY OF THE INVENTION

[0011] Accordingly, the present inventors have made studies in variety,taking note of hexaborides, which have free electrons in a largequantity. As the result, they have succeeded in making up a master batchcontaining a heat radiation shielding component, obtained by making ahexaboride into ultrafine particles and dispersing the ultrafineparticles in a thermoplastic resin by a conventional mixing means.

[0012] They have also discovered that the master batch containing a heatradiation shielding component may be diluted and mixed with athermoplastic resin form material and the mixture obtained may be formedin any desired shapes of a sheet or plate, a film, a sphere and so forthby a known method such as extrusion, injection molding or compressionmolding and this enables production of a heat radiation shieldingtransparent resin form and a heat radiation shielding transparentlaminate that have a maximum transmittance in the visible light regionand also show a strong absorption, and have a minimum transmittance, inthe infrared region. The present invention has been accomplished basedon such technical discoveries.

[0013] More specifically, an object of the present invention is toprovide a master batch containing a heat radiation shielding componentby the use of which (master batch) heat radiation shielding transparentresin forms of various shapes, having a high heat radiation shieldingperformance while maintaining a superior visible-light transmissionpower, can be produced by a simple method without use of any high-costphysical film formation methods.

[0014] Another object of the present invention is to provide a heatradiation shielding transparent resin form, and a heat radiationshielding transparent laminate, for which the master batch containing aheat radiation shielding component has been used.

[0015] That is, the master batch containing a heat radiation shieldingcomponent, which is used to produce heat radiation shielding transparentresin forms, comprises as chief components a thermoplastic resin and ahexaboride represented by XB₆, wherein X is at least one selected fromLa, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr and Ca;

[0016] the hexaboride, which is a heat radiation shielding component,being contained in an amount of from 0.01 part by weight or more to lessthan 20 parts by weight based on 100 parts by weight of thethermoplastic resin.

[0017] The heat radiation shielding transparent resin form of thepresent invention is characterized by being obtained by diluting andmixing the above master batch containing a heat radiation shieldingcomponent, with a thermoplastic-resin form material of the same type asthe thermoplastic resin of the master batch or a different type ofthermoplastic-resin form material having a compatibility with the masterbatch, and forming (extruding or molding) the resulting mixture in astated shape.

[0018] The heat radiation shielding transparent laminate of the presentinvention is also characterized by being obtained by laminating theabove heat radiation shielding transparent resin form to othertransparent form.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention is described below in detail.

[0020] The master batch of the present invention is used to produce heatradiation shielding transparent resin forms, and contains as chiefcomponents a thermoplastic resin and a hexaboride which is a heatradiation shielding component.

[0021] The master batch containing a heat radiation shielding componentaccording to the present invention is prepared by uniformly dispersingin a thermoplastic resin fine hexaboride XB₆ particles serving as theheat radiation shielding component. The hexaboride used in the presentinvention may typically include lanthanum hexaboride (LaB₆), ceriumhexaboride (CeB₆), praseodymium hexaboride (PrB₆), neodymium hexaboride(NdB₆), gadolinium hexaboride (GdB₆), terbium hexaboride (TbB₆),dysprosium hexaboride (DyB₆), holmium hexaboride (HOB₆), yttriumhexaboride (YB₆), samarium hexaboride (SmB₆), europium hexaboride(EuB₆), erbium hexaboride (ErB₆), thulium hexaboride (TmB₆), ytterbiumhexaboride (YbB₆), lutetium hexaboride (LuB₆), lanthanum-ceriumhexaboride [(La, Ce) B₆], strontium hexaboride (SrB₆) and calciumhexaboride (CaB₆).

[0022] As the fine hexaboride particles used in the present invention,their surfaces may preferably not stand oxidized. In many cases,however, they usually stand slightly oxidized, and also it can not beavoided to a certain extent that the oxidation of surfaces takes placein the step of dispersing the fine particles. Even in such a case,however, there is no change in the effectiveness of showing heatradiation shielding effect. Hence, it is also possible to use finehexaboride particles standing surface-oxidized.

[0023] These fine hexaboride particles also have a greater heatradiation shielding effect as they have a higher perfectness ascrystals. However, even those having so low crystallizability as to forma broad diffraction peak in X-ray diffraction may be used in the presentinvention because they can show a heat radiation shielding effect aslong as the basic bonds in the interiors of the fine particles consistof bonds between each metal and boron.

[0024] These fine hexaboride particles are also in the form of a powderhaving color such as grayish black, brownish black or greenish black.If, however, they are made to have a particle diameter sufficientlysmaller than visible-light wavelength and brought into a state that theyhave been dispersed in the heat radiation shielding transparent resinform, the visible-light transmission properties come therefrom in theheat radiation shielding transparent resin form. Nevertheless, theinfrared shielding power can sufficiently be retained. The reasontherefor has not been elucidated in detail. It is presumed that the freeelectrons in these fine particles are in a large quantity and theabsorption energy of indirect transition between bands that is due tofree electrons in the interiors, and at the surfaces, of the fineparticles is just in the vicinities of from visible to infrared, andhence the heat radiations in this wavelength region are selectivelyreflected and absorbed.

[0025] According to experiments, it has been observed that, in a film inwhich any of these fine particles has well finely and uniformly beendispersed, its transmittance has a maximum value at wavelengths between400 nm and 700 nm and has a minimum value at wavelengths between 700 nmand 1,800 nm, and also that the difference in transmittance betweenthese maximum value and minimum value is 15 points or more. Takingaccount of a hanging bell type that the visible-light wavelength is 380nm to 780 nm and the visibility has a peak at about 550 nm, such a heatradiation shielding transparent resin form has characteristics that ittransmits visible light effectively and reflects and absorbs the otherradiations effectively.

[0026] Here, the above fine hexaboride particles have very high heatradiation shielding power per unit weight. It has been ascertained thatthey exhibit their effect when they are used in an amount of {fraction(1/30)} or less, compared with tin-doped indium oxide (ITO; see JapanesePatent Application Laid-open No. 7-69632) and antimony-doped tin oxide(ATO) which are utilized as infrared radiation cut-off powders. Hence,the amount of the whole fine particles to be used can vastly be cutdown. This enables dissolution of the problem in view of strength thatthe transparent resin forms may have low physical properties, inparticular, a low impact resistance and a low toughness; the problembeing caused when the heat radiation shielding particles are mixed inthe heat radiation shielding transparent resin form in a large quantity.In addition, the fine hexaboride particles have absorption in thevisible-light region when used in a large quantity, and hence theabsorption in the visible-light region can freely be controlled bycontrolling the quantity of the particles to be added, also making itpossible to adjust brightness or to apply the forms toprivacy-protective parts or the like.

[0027] As to the particle diameter of the fine hexaboride particles usedin the present invention, it may be arbitrary as long as they functionas the heat radiation shielding component. The fine hexaboride particlesmay preferably have an average particle diameter of 1,000 nm or less,and more preferably 200 nm or less. This is because any fine particleshaving an average particle diameter larger than 1,000 nm or coarseparticles formed by agglomeration of fine particles may act as a lightscattering source of the heat radiation shielding transparent resin formproduced and the transparent resin form looks cloudy. As the lowerlimit, there is no particular limitation. The fine hexaboride particlesmay preferably have particle diameter as small as possible, as long assuch particles can be produced (actually, it is difficult to producehexaboride particles having a diameter of less than 1 nm).

[0028] However, transparent roofing materials or the like may berequired to have light transmission properties which are opaque ratherthan transparent. In such a case, the heat radiation shieldingtransparent resin form may preferably be so constructed that particleshaving larger particle diameter are used so as to promote lightscattering. However, particles larger than 1,000 nm may causeattenuation of the heat radiation shielding power itself, and hence theymay preferably have the average particle diameter of 1,000 nm or less,and more preferably from 500 nm to 600 nm.

[0029] As the fine hexaboride particles used in the present invention,those having been surface-treated with a silane compound, a titaniumcompound or a zirconia compound may be used. The treatment offine-particle surfaces with such a compound enables improvement in waterresistance of the hexaboride.

[0030] As to the thermoplastic resin used in the present invention,there are no particular limitations as long as it is a transparentthermoplastic resin having high light transmission properties in thevisible-light region. For example, it may include thermoplastic resinshaving, when the heat radiation shielding transparent resin form isformed in a plate of 3 mm in thickness, a visible-light transmittance of50% or more as prescribed in JIS R 3106 and a haze of 30% or less asprescribed in JIS K 7105. Stated specifically, it may include acrylicresins, polycarbonate resins, polyether-imide resins, polyester resins,polystyrene resins, polyether-sulfone resins, fluorine resins andpolyolefin resins. Where it is intended to use the heat radiationshielding transparent resin form in window materials or the like ofvarious buildings and vehicles, acrylic resins, polycarbonate resins,polyether-imide resins and fluorine resins are preferred taking accountof transparency, impact resistance, weatherability and so forth.

[0031] As the polycarbonate resins, aromatic polycarbonates arepreferred. The aromatic polycarbonates may include polymers obtainedfrom at least one divalent phenolic compound typified by2,2-bis(4-hydroxyphenyl)propane or2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane and a carbonate precursortypified by phosgene or diphenyl carbonate, and by a known process suchas interfacial polymerization, solution polymerization or solid-phasepolymerization.

[0032] The acrylic resins may include polymers or copolymers obtainedusing as a chief raw material methyl methacrylate, ethyl methacrylate,propyl methacrylate or butyl methacrylate and optionally using as acopolymer component an acrylic ester having an alkyl group having 1 to 8carbon atoms, vinyl acetate, styrene, acrylonitrile ormethacrylonitrile. Acrylic resins obtained by more multi-stagepolymerization may also be used.

[0033] The fluorine resins may include polyfluoroethylene,polydifluoroethylene, polytetrafluoroethylene, anethylene-difluoroethylene copolymer, an ethylene-tetrafluoroethylenecopolymer and tetrafluoroethylene-perfluoroalkoxyethylene copolymers.

[0034] As to the content of the hexaboride in respect to thethermoplastic resin, the hexaboride may be in a content of from 0.01part by weight or more to less than 20 parts by weight, and preferablyfrom 0.1 part by weight or more to 10 parts by weight or less, based on100 parts by weight of the thermoplastic resin. If the content of thehexaboride is larger than this range, the fine hexaboride particles maymutually agglomerate to come dispersed insufficiently in the resin, sothat the heat radiation shielding transparent resin form produced mayhave a high haze value. There is also a possibility of causing dilutionnon-uniformity when the master batch containing the heat radiationshielding component (hereinafter often “HRS-component-containing masterbatch”) is diluted and mixed with a thermoplastic-resin form material.If on the other hand the content of the hexaboride is smaller than theabove range, any sufficient heat radiation shielding power may be notobtainable especially when the transparent resin form produced is a filmof 100 μm or less in thickness, depending on the thickness of the heatradiation shielding transparent resin form produced.

[0035] As methods of dispersing the fine hexaboride particles in thethermoplastic resin, any methods may be selected as long as they aremethods by which the fine particles can uniformly be dispersed in theresin. For example, a method may be used in which the fine hexaborideparticles are dispersed in any desired solvent by means of a bead mill,a ball mill or a sand mill or by ultrasonic dispersion to prepare adispersion of the fine hexaboride particles, and this dispersion andpowder or pellets of the thermoplastic resin, optionally together withother additive(s), are uniformly melt-mixed by means of a mixing machinesuch as a ribbon blender, a tumbling mixer, a Nauta mixer, a Henschelmixer, a super mixer or a planetary-screw mixer and a kneading machinesuch as a Banbury mixer, a kneader, a roll mill, a single-screw extruderor a twin-screw extruder while removing the solvent, thus a mixture canbe prepared in which the fine hexaboride particles have uniformly beendispersed in the thermoplastic resin. The mixture in which the finehexaboride particles have uniformly been dispersed in the thermoplasticresin may also be prepared by a method in which the solvent in thedispersion of the fine hexaboride particles is removed by a known methodand the powder obtained and the powder or pellets of the thermoplasticresin, optionally together with other additive(s), are uniformlymelt-mixed. Besides, a method may be used in which powder of the finehexaboride particles having not been subjected to dispersion treatmentis directly added to the thermoplastic resin and these are uniformlymelt-mixed. It may suffice for the fine hexaboride particles to beuniformly dispersed in the thermoplastic resin, and methods are notlimited to these.

[0036] The mixture thus obtained may be kneaded by means of a ventedsingle-screw extruder or twin-screw extruder and then worked intopellets to obtain the HRS-component-containing master batch of thepresent invention.

[0037] The pellets may be obtained by a most commonly available methodin which melt-extruded strands are cut. Thus, as their shapes, acolumnar shape and a prismatic shape are available. It is also possibleto employ “hot-cut pelletizing”, in which the melt-extruded product isdirectly cut. In such a case, it is common for the pellets to have aclosely spherical shape.

[0038] Thus, the HRS-component-containing master batch of the presentinvention may employ any form or any shape. It may preferably be in thesame form and shape as those of the thermoplastic-resin form materialused to dilute the master batch when the heat radiation shieldingtransparent resin form is formed.

[0039] The heat radiation shielding transparent resin form according tothe present invention is obtained by diluting and mixing theHRS-component-containing master batch with a thermoplastic-resin formmaterial of the same type as the thermoplastic resin of the master batchor a different type of thermoplastic-resin form material having acompatibility with the master batch and the mixture obtained is formedin a stated shape.

[0040] As the shape of the heat radiation shielding transparent resinform, the resin form may be formed in any shape as desired, and may bein a flat shape or a curved shape. As to the thickness of the heatradiation shielding transparent resin form as well, it may be set to anydesired thickness according to what is necessary for the shapes of aplate and up to a film. A resin sheet formed in a flat shape may beformed by post working in any desired shape such as a spherical shape.

[0041] As methods of forming the heat radiation shielding transparentresin form, any methods such as injection molding, extrusion,compression molding and rotary molding are available. In particular, amethod of obtaining the form by injection molding and a method ofobtaining the form by extrusion may preferably be employed. As a methodof obtaining a sheet- or platelike or filmlike form by the extrusion,such a form is produced by a method in which a molten thermoplasticresin extruded using an extruder such as a T-die is taken off whilebeing cooled by means of a cooling roll. Forms obtained by the injectionmolding are preferably used in the bodies of cars such as window glassand roofs of automobiles. Sheet- or platelike or filmlike forms obtainedby the extrusion are preferably used in constructions such as arcadesand carports.

[0042] The heat radiation shielding transparent resin form itself may beused alone in structural materials such as window glass and arcades, andbesides may be used in the structural materials, as an integral heatradiation shielding transparent laminate obtained by laminating thetransparent resin form to other transparent forms such as inorganicglass sheets, resin glass sheets or resin films by any desired method.For example, a heat radiation shielding transparent resin formbeforehand formed in the shape of film may be laminated to andintegrated with an inorganic glass sheet by heat lamination to obtain aheat radiation shielding transparent laminate having heat radiationshielding performance and scattering preventive performance. Also, atthe same time when the heat radiation shielding transparent resin formis formed, it may be laminated to and integrated with other transparentform by heat lamination, co-extrusion, press molding, injection moldingor the like to obtain the heat radiation shielding transparent laminate.Such a heat radiation shielding transparent laminate can be used as amore useful structural material because it can complement any eachother's disadvantages while effectively exhibiting each other'sadvantages the both forms have.

[0043] The master batch containing the heat radiation shieldingcomponent according to the present invention may further be mixed withany of commonly available additives. For example, usable as additivesare dyes or pigments such as azo dyes, cyanine dyes, quinoline dyes,perylene dyes and carbon black which are commonly used to colorthermoplastic resins in order to impart any desired color tones asoccasion calls; as well as hindered-phenol type or phosphorus typestabilizers; release agents; hydroxybenzophenone type, salicylic acidtype, HALS type, triazole type or triazine type ultraviolet absorbers;coupling agents; surface-active agents; antistatic agents and so forth;any of which may be mixed in an effective quantity.

[0044] The use of the HRS-component-containing master batch according tothe present invention, in which the hexaboride has uniformly beendispersed as the heat radiation shielding component in the thermoplasticresin as described above in detail, makes it possible to provide theheat radiation shielding transparent resin form and the heat radiationshielding transparent laminate which have a high heat radiationshielding performance and also have a high transmission power in thevisible-light region, without use of any high-cost physical filmformation methods and any complicated process.

[0045] The resulting heat radiation shielding transparent resin form andheat radiation shielding transparent laminate, when used as materialsfor windows of automobiles and buildings, carports, arcades and soforth, also have the effect of shielding the solar energy that may entertherethrough, to reduce a load of air conditioning (cooling) and lessena feeling of the heat, and at the same time have the effect of beinguseful for energy saving and having a high utility from an environmentalviewpoint.

[0046] The present invention is described below in greater detail bygiving Examples. The present invention is by no means limited by thefollowing Examples.

[0047] In the following Examples, only examples making use of lanthanumhexaboride are described. It, however, has been ascertained that, likeExamples disclosed in Japanese Patent Application Laid-open No.2000-96034 as proposed by the present applicant, the same effect as thatin the lanthanum hexaboride is obtainable in respect of otherhexaborides as well.

EXAMPLE 1

[0048] 200 g of fine lanthanum hexaboride (LaB₆) particles of 67 nm inaverage particle diameter as a heat radiation shielding component, 700 gof toluene and appropriate amounts of water and a dispersant were mixed,and the mixture obtained was further mixed for 100 hours by means of aball mill making use of zirconia balls of 4 mm in diameter to prepare 1kg of a dispersion of fine lanthanum hexaboride particles (hereinaftersimply “liquid A”).

[0049] Further, the toluene in the liquid A was removed using a spraydryer to obtain a disperse powder of fine lanthanum hexaboride particles(hereinafter simply “powder A”).

[0050] Next, to pellets of a thermoplastic resin polycarbonate resin,the powder A thus obtained was so added as to be in an LaB₆concentration of 2.0% by weight (corresponding to 2.0 parts by weightbased on 100 parts by weight of the resin), and these were uniformlymixed by means of a blender, followed by melt-kneading using atwin-screw extruder. Strands extruded therefrom were cut into pellets toobtain a master batch containing the heat radiation shielding component(hereinafter simply “master batch A”).

[0051] Next, the master batch A and polycarbonate resin pellets wereuniformly so mixed by means of a blender that the former was dilutedwith the latter to give an LaB₆ concentration of 0.01% by weight,followed by extrusion using a T-die, into a sheet of 1.0 mm in thicknessto obtain a heat radiation shielding transparent resin form in which thefine lanthanum hexaboride particles stood uniformly dispersed in thewhole resin.

[0052] Spectral characteristics of the heat radiation shieldingtransparent resin form (polycarbonate sheet) thus produced were measuredwith a spectrophotometer U-4000, manufactured by Hitachi Ltd., andsolar-radiation transmittance and visible-light transmittance werecalculated according to JIS R 3106.

[0053] Results obtained are shown in Table 1.

EXAMPLE 2

[0054] A master batch containing a heat radiation shielding componentwas obtained in the same manner as in Example 1 except that acrylicresin was used as the thermoplastic resin to prepare the pellets. Morespecifically, the powder A and acrylic resin pellets were so mixed as togive the numerical value as shown in the column “Master batchcomposition” in Table 1, and were melt-kneaded using a twin-screwextruder. Strands extruded therefrom were cut into pellets to obtain amaster batch containing the heat radiation shielding component accordingto this Example (hereinafter simply “master batch B”).

[0055] Next, a heat radiation shielding transparent resin form wasobtained in the same manner as in Example 1 except that the master batchwas diluted with acrylic resin pellets. More specifically, the masterbatch B and acrylic resin pellets were uniformly so mixed by means of ablender that the former was diluted with the latter to give thenumerical value as shown in the column “Composition of heat radiationshielding transparent resin form” in Table 1, followed by extrusionusing a T-die, into a sheet of 1.0 mm in thickness to obtain a heatradiation shielding transparent resin form in which the fine lanthanumhexaboride particles stood uniformly dispersed in the whole resin.Spectral characteristics of this heat radiation shielding transparentresin form are also shown in Table 1.

EXAMPLE 3

[0056] A master batch containing a heat radiation shielding componentwas obtained in the same manner as in Example 1 except thatpolyether-imide resin was used as the thermoplastic resin to prepare thepellets. More specifically, the powder A and polyether-imide resinpellets were so mixed as to give the numerical value as shown in thecolumn “Master batch composition” in Table 1, and were melt-kneadedusing a twin-screw extruder. Strands extruded therefrom were cut intopellets to obtain a master batch containing the heat radiation shieldingcomponent according to this Example (hereinafter simply “master batchC”).

[0057] Next, a heat radiation shielding transparent resin form wasobtained in the same manner as in Example 1 except that the master batchwas diluted with polyether-imide pellets. More specifically, the masterbatch C and polyether-imide resin pellets were uniformly so mixed bymeans of a blender that the former was diluted with the latter to givethe numerical value as shown in the column “Composition of heatradiation shielding transparent resin form” in Table 1, followed byextrusion using a T-die, into a sheet of 1.0 nm in thickness to obtain aheat radiation shielding transparent resin form in which the finelanthanum hexaboride particles stood uniformly dispersed in the wholeresin. Spectral characteristics of this heat radiation shieldingtransparent resin form are also shown in Table 1.

Example 4

[0058] A master batch containing a heat radiation shielding componentwas obtained in the same manner as in Example 1 except that polyethyleneterephthalate resin was used as the thermoplastic resin to prepare thepellets. More specifically, the powder A and polyethylene terephthalateresin pellets were so mixed as to give the numerical value as shown inthe column “Master batch composition” in Table 1, and the subsequentprocedure in Example 1 was repeated to obtain a master batch containingthe heat radiation shielding component according to this Example(hereinafter simply “master batch D”).

[0059] Next, this master batch D and polyethylene terephthalate resinpellets were uniformly so mixed by means of a blender that the formerwas diluted with the latter to give the numerical value as shown in thecolumn “Composition of heat radiation shielding transparent resin form”in Table 1, followed by extrusion using a T-die, into a film of 0.1 mmin thickness to obtain a heat radiation shielding transparent resin formin which the fine lanthanum hexaboride particles stood uniformlydispersed in the whole resin. Spectral characteristics of this heatradiation shielding transparent resin form are also shown in Table 1.

EXAMPLE 5

[0060] A master batch containing a heat radiation shielding componentwas obtained in the same manner as in Example 1 except that ETFE(ethylene-tetrafluoroethylene copolymer) resin was used as thethermoplastic resin to prepare the pellets. More specifically, thepowder A and ETFE resin pellets were so mixed as to give the numericalvalue as shown in the column “Master batch composition” in Table 1, andthe subsequent procedure in Example 1 was repeated to obtain a masterbatch containing the heat radiation shielding component according tothis Example (hereinafter simply “master batch E”).

[0061] Next, a heat radiation shielding transparent resin form wasobtained in the same manner as in Example 4 except that the master batchwas diluted with ETFE pellets. More specifically, the master batch E andETFE resin pellets were so mixed that the former was diluted with thelatter to give the numerical value as shown in the column “Compositionof heat radiation shielding transparent resin form” in Table 1, and thesubsequent procedure in Example 4 was repeated to obtain a heatradiation shielding transparent resin form in which the fine lanthanumhexaboride particles stood uniformly dispersed in the whole resin.Spectral characteristics of this heat radiation shielding transparentresin form are also shown in Table 1.

EXAMPLE 6

[0062] To 950 g of the liquid A, 50 g of methyltrimethoxysilane wasadded, and these were stirred by mean of a mechanical stirrer.Thereafter, the toluene in the liquid A was removed using a spray dryerto obtain a disperse powder of fine lanthanum hexaboride particlessurface-treated with a silane compound (hereinafter simply “powder B”).

[0063] Next, in the same manner as in Example 1, the powder B andpolycarbonate resin pellets were so mixed as to give the numerical valueas shown in the column “Master batch composition” in Table 1, and thesubsequent procedure in Example 1 was repeated to obtain a master batchcontaining the heat radiation shielding component according to thisExample (hereinafter simply “master batch F”).

[0064] Then, in the same manner as in Example 1, the master batch F andpolycarbonate resin pellets were so mixed that the former was dilutedwith the latter to give the numerical value as shown in the column“Composition of heat radiation shielding transparent resin form” inTable 1, and the subsequent procedure in Example 1 was repeated toobtain a heat radiation shielding transparent resin form in which thefine lanthanum hexaboride particles stood uniformly dispersed in thewhole resin. Spectral characteristics of this heat radiation shieldingtransparent resin form (polycarbonate sheet) are also shown in Table 1.

COMPARATIVE EXAMPLE

[0065] To pellets of a thermoplastic resin polycarbonate resin, thepowder A was so added as to be in an LaB₆ concentration of 16.7% byweight (corresponding to 20.0 parts by weight based on 100 parts byweight of the resin), and these were uniformly mixed by means of ablender, followed by melt-kneading using a twin-screw extruder. Strandsextruded therefrom were cut into pellets to obtain a master batchcontaining the heat radiation shielding component (hereinafter simply“master batch G”).

[0066] Next, the master batch G and polycarbonate resin pellets wereuniformly so mixed by means of a blender that the former was dilutedwith the latter to give an LaB₆ concentration of 0.01% by weight,followed by extrusion using a T-die, into a sheet of 1.0 mm in thicknessto obtain a heat radiation shielding transparent resin form according toComparative Example, in which the fine lanthanum hexaboride particlesstood uniformly dispersed in the whole resin. Spectral characteristicsof this heat radiation shielding transparent resin form are also shownin Table 1. TABLE 1 Composition of heat radiation Spectral shieldingcharacteristics transparent Thickness Visible = Solar Master batchcomposition resin form of trans- light radiation LaB₆ LaB₆ parent trans-trans- conc. concentration resin form mittance mittance Resin used (pbw)(wt. %) (mm) (%) (%) Example: 1 Polycarbonate  2.0 0.01 1.0 78.2 58.9 2Acrylic  5.3 0.01 1.0 78.0 59.0 3 Polyether-  2.0 0.01 1.0 77.9 58.5imide 4 Polyethylene  3.1 0.10 0.1 78.5 58.8 terephthalate 5 Ethylene- 2.0 0.10 0.1 78.4 58.4 tetrafluoroethylene 6 Polycarbonate  2.0 0.011.0 77.7 59.0 Comparative Example: Polycarbonate 20.0 0.01 1.0 82.3 63.0

[0067] Evaluation

[0068] 1. Evaluation of external appearance of HRS-component-containingmaster batches and heat radiation shielding transparent resin formsaccording to Examples and Comparative Example:

[0069] In the HRS-component-containing master batch according toComparative Example, its LaB₆ content was as large as 20.0 parts byweight based on 100 parts by weight of the polycarbonate resin, andhence it was unable to disperse the fine LaB₆ particles uniformly whenthe master batch was prepared. As the result, coarse particles were seenin the heat radiation shielding transparent resin form produced usingthe HRS-component-containing master batch according to ComparativeExample, and this form had a rough surface.

[0070] In the step of diluting the HRS-component-containing master batchaccording to Comparative Example with the polycarbonate resin pellets,the master batch was added to the polycarbonate resin pellets in a verysmall quantity (since the LaB₆ content was as large as 20.0 parts byweight based on 100 parts by weight of the polycarbonate resin, itfollows that the mixing proportion of the HRS-component-containingmaster batch to the polycarbonate resin pellets for dilution is thesmaller). Hence, the fine LaB₆ particles did not stand uniformlydispersed in the resin form, and color shadings were seen. It has alsobeen ascertained that, because of such non-uniform distribution, thesolar-radiation transmittance of the heat radiation shieldingtransparent resin form according to Comparative Example shows anumerical value of 63.0%, which is poorer than those of the heatradiation shielding transparent resin forms according to Examples.

[0071] On the other hand, in respect of the HRS-component-containingmaster batches according to Examples, in which the LaB₆ content is setto from 0.01 part by weight or more to less than 20 parts by weight, thedisadvantages as in Comparative Example are not seen and it has beenascertained that good heat radiation shielding transparent resin formscan be produced using the HRS-component-containing master batchesaccording to Examples.

[0072] 2. Evaluation of water resistance test of heat radiationshielding transparent resin forms according to Examples 1 and 6:

[0073] To evaluate the water resistance of the heat radiation shieldingtransparent resin forms according to Examples 1 and 6, their waterresistance was compared with that of the following heat radiationshielding transparent laminate produced using a heat radiation shieldingcoating liquid prepared by incorporating fine hexaboride particles in aninorganic binder.

[0074] (Production of Heat Radiation Shielding Transparent Laminate)

[0075] An ethyl silicate solution prepared using 10 g of Ethyl Silicate40, available from Tama Chemical Co., Ltd., a tetra- to pentamer inlight of its average degree of polymerization, 27 g of ethanol, 8 g ofan aqueous 5% hydrochloric acid solution and 5 g of water was thoroughlymixed and stirred to prepare 50 g of a liquid ethyl silicate mixture(hereinafter simply “liquid B”).

[0076] Next, the liquid A in Example 1 and this liquid B were mixed, andthe resulting mixture was further so diluted with diacetone alcohol asto have an LaB₆ concentration of 0.2% by weight and an SiO2concentration of 2.5% by weight, to prepare a heat radiation shieldingcoating liquid.

[0077] Then, 15 g of this heat radiation shielding coating liquid wascoated on a polycarbonate sheet of 2.0 mm in thickness by means of aspin coater, and this coated sheet was put into a 100° C. electricfurnace and then heated for 30 minutes to produce a heat radiationshielding transparent laminate having a heat radiation shielding filmformed on the polycarbonate sheet. Spectral characteristics of this heatradiation shielding transparent laminate were measured to find that itsvisible-light transmittance and solar-radiation transmittance were 78%and 57.9%, respectively.

[0078] Next, the heat radiation shielding transparent laminate thusobtained was stored for 100 days in a thermo-hygrostat conditioned at atemperature of 80° C. and a humidity of 95% RH, and then its spectralcharacteristics were again measured to find that the visible-lighttransmittance and the solar-radiation transmittance were 81% and 62.4%,respectively, showing an increase in visible-light transmittance andsolar-radiation transmittance by 3% and 4.5%, respectively.

[0079] Meanwhile, the heat radiation shielding polycarbonate sheetobtained in Example 1 was stored for 100 days in the thermo-hygrostatconditioned at a temperature of 80° C. and a humidity of 95% RH, andthen its spectral characteristics were again measured to find that thevisible-light transmittance and the solar-radiation transmittance were78.5% and 59.2%, respectively, showing a slight increase invisible-light transmittance and solar-radiation transmittance by 0.3%and 0.3%, respectively.

[0080] The heat radiation shielding polycarbonate sheet obtained inExample 6 was also stored for 100 days in the thermo-hygrostatconditioned at a temperature of 80° C. and a humidity of 95% RH, andthen its spectral characteristics were again measured to find that thevisible-light transmittance and the solar-radiation transmittance were77.7% and 59.0%, respectively, showing no change in spectralcharacteristics.

[0081] From these results, it is ascertained that, in the heat radiationshielding transparent laminate obtained using the heat radiationshielding coating liquid, because of its very thin heat radiationshielding film, a large number of fine lanthanum hexaboride particlescome into contact with water content to cause decomposition of the finelanthanum hexaboride particles to lower the laminate's heat radiationshielding performance.

[0082] On the other hand, it is ascertained that, in the heat radiationshielding polycarbonate sheet obtained in Example 1, the fine lanthanumhexaboride particles are uniformly dispersed in the polycarbonate resin,and the fine lanthanum hexaboride particles less come into contact withwater content to bring an improvement in water resistance.

[0083] It is also ascertained that, in the heat radiation shieldingpolycarbonate sheet obtained in Example 6, its water resistance has beenmore improved than the heat radiation shielding polycarbonate sheetobtained in Example 1, because the fine lanthanum hexaboride particlessurface-treated with the silane coupling agent are used.

What is claimed is:
 1. A master batch containing a heat radiationshielding component, which is used to produce heat radiation shieldingtransparent resin forms; the master batch comprising: as chiefcomponents a thermoplastic resin and a hexaboride represented by XB₆,wherein X is at least one selected from La, Ce, Pr, Nd, Gd, Tb, Dy, Ho,Y, Sm, Eu, Er, Tm, Yb, Lu, Sr and Ca; said hexaboride, which is a heatradiation shielding component, being contained in an amount of from 0.01part by weight or more to less than 20 parts by weight based on 100parts by weight of said thermoplastic resin.
 2. The master batchaccording to claim 1, wherein said thermoplastic resin is at least oneselected from an acrylic resin, a polycarbonate resin, a polyether-imideresin, a polystyrene resin, a polyether-sulfone resin, a fluorine resin,a polyolefin resin and a polyester resin.
 3. The master batch accordingto claim 1 or 2, wherein said hexaboride comprises fine particles havingan average particle diameter of 1,000 nm or less.
 4. The master batchaccording to claim 1 or 2, wherein said hexaboride have beensurface-treated with at least one selected from a silane compound, atitanium compound and a zirconia compound.
 5. A heat radiation shieldingtransparent resin form characterized by being obtained by diluting andmixing the master batch according to claim 1 with a thermoplastic-resinform material of the same type as the thermoplastic resin of the masterbatch or a different type of thermoplastic-resin form material having acompatibility with the master batch, and forming the resulting mixturein a stated shape.
 6. A heat radiation shielding transparent laminatecharacterized by being obtained by laminating the heat radiationshielding transparent resin form according to claim 5 to othertransparent form.